Ansible 2.0 delegate_to user not working

[Matt Knox]

I had an automatic upgrade push me up to ansible 2.0.0.2 today (from 1.9.4) and that broke some of my playbooks. I think that there may be a bug related to delegate_to, as it was using the user None instead of the user for the playbook. I tried to set remote_user in the task as well, that made no difference. I ended up rolling back to 1.9.4 and that worked just fine.

<IP_ADDR> ESTABLISH SSH CONNECTION FOR USER: None <IP_ADDR> SSH: EXEC ssh -C -q -o ControlMaster=auto -o ControlPersist=60s -o StrictHostKeyChecking=no -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o ConnectTimeout=10 -o ControlPath=/tmp/ansible_tower_Y0z0IW/cp/ansible-ssh-%h-%p-%r -tt tower.platform.sphero.com '( umask 22 && mkdir -p "$( echo $HOME/.ansible/tmp/ansible-tmp-1452893833.75-87410177372175 )" && echo "$( echo $HOME/.ansible/tmp/ansible-tmp-1452893833.75-87410177372175 )" )' fatal: [IP]: UNREACHABLE! => {"changed": false, "msg": "ERROR! SSH encountered an unknown error during the connection. We recommend you re-run the command using -vvvv, which will enable SSH debugging output to help diagnose the issue", "unreachable": true}